Knitting machines

ABSTRACT

In a knitting machine having at least two co-operating arrays of independently actuable latch needles arranged in opposed needle beds, a carrier located above the needle beds and movable longitudinally of the needle beds and a hold-down element supported from the carrier for holding down knitted loops as the needles rise, the carrier is mounted so as to be capable of movement between a first level and a second level which is raised in relation to the first level. Movement of the carrier to said second level, caused for example by the hold-down element striking a needle which has failed to descend, is employed to actuate means for producing a warning signal and/or for stopping the knitting machine.

United States Patent Flavell et al.

[451 Dec. 16, 1975 1 KNITTING MACHINES [75] Inventors: John Flavell, Coundon, Coventry; Keith Jeffcoat, Nuneaton, both of England [73] Assignee: Courtaulds Limited, London,

England 22 Filed: May 2, 1974 [21] Appl. No.: 466,310

[30] Foreign Application Priority Data May 10, 1973 United Kingdom 22311/73 [52] US. Cl. 66/157 [51] Int. Cl. D04B 35/10 [58] Field of Search 66/157, 147, 165, 78, 64

[56] References Cited FOREIGN PATENTS OR APPLICATIONS 772,227 10/1934 France 66/157 625,979 7/1949 United Kingdom... 66/157 327,936 4/1920 Germany 66/157 216,442 9/1907 Germany 66/157 77,790 l/l9l8 Switzerland 66/157 443,818 3/1930 Germany 66/157 14,732 6/1908 United Kingdom I t .1 66/157 14,937 7/1897 Switzerland I I t 66/157 105,690 10/1898 Germany 66/157 Primary E.\'aminerRonald Feldbaum Attorney, Agent, or FirmDavis, Hoxie, Faithfull & Hapgood needles rise, the carrier is mounted so as to be capable of movement between a first level and a second level which is raised in relation to the first level. Movement of the carrier to said second level, caused for example by the hold-down element striking a needle which has failed to descend, is employed to actuate means for producing a warning signal and/or for stopping the knitting machine.

7 Claims, 7 Drawing Figures US. Patent Dec.16,1975 SheetlofS 3,926,016

U.S. Patent Dec. 16, 1975 Sheet 2 of5 3,926,016

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U.S. Patent Dec. 16, 1975 Sheet 3 of5 3,926,016

US. Patent Dec. 16,1975 Sheet40f5 3,926,016

US. Patent Dec. 16, 1975 SheetSofS 3,926,016

KNITTING MACHINES This invention relates to a knitting machine of the kind having at least two co-operating arrays of latch needles arranged in opposed needle beds and means for independent actuation of successive needles in the arrays.

It is known to provide a knitting machine of the kind referred to with at least one hold-down element to cooperate in the knitting action in such a way as to hold down the loops on the needles as the needles rise, thereby opening the latches and causing the loops to lie on the needle shanks below the latches so as to close them and then pass over the latches as the needles descend. One example of a knitting machine of the kind referred to provided with two hold-down elements is described and claimed in our US. Pat. No. 3,613,401 hereinafter referred to as the aforesaid Specification.

The hold-down element is supported from a carrier arranged above the needle beds and movable longitudinally of the needle beds in synchronism with the actuation of the needles. For example, this carrier may be.se cured to the cam carriage of the machine or a part associated therewith.

If, during the' operation of a knitting machine of the kind referred to which is provided with such a holddown element, the element encounters an obstruction, damage can be caused. For example, if one of the needles of the machine, due to some defect, remains in a raised position instead of descending, the hold-down element will strike the raised needle, causing damage to the raised needle and/or to the hold-down element. Damage may also be caused to the needle beds and to other needles. If the machine is not sufficiently damaged to prevent it from knitting, and if such an occurrence is not immediately detected by the person supervising the knitting machine, the knitted fabric produced subsequent to the damage to the needle and/or the hold-down element may be defective, and the fact that the fabric is defective may not be observed until a considerable length of fabric has been knitted.

The present invention aims to provide an improved knitting machine of the kind referred to and provided with at least one hold-down element in which there is a reduced risk of defective fabric being knitted after the hold-down element has struck a raised needle.

According to the invention, in a knitting machine of the kind referred to and comprising a carrier having a hold-down element depending from it, the carrier is located above the needle beds, is movable longitudinally of the needle beds and is also capable of movement between a first level and a second level which is raised in relation to the first level, and is arranged when moving to said second level to actuate means for producing a warning signal and/or for stopping the knitting ma chine.

References in this specification to positions of parts in relation to other parts and to directions of movement of the needles are given in adoption of the convention that the needles move up to take yarn and move down to draw a loop. Such references do not necessarily indicate any particular attitude, in relation to the vertical, of the needles or the parts of the machine in which they are incorporated.

The carrier may be in the form of an elongate member supported at each end in a bracket which is mounted on an associated support located above the needle beds, for example a bridge member extending between the two cam boxes of the machine and thus across and above the needle beds. The brackets which support the carrier may be hingedly mounted, each on its associated support and one of them may be mounted on the associated support member so as to be also capable of pivotal movement about a horizontal axis.

The carrier may be urged to said first level by gravity and/or by suitably arranged spring means.

The means for producing a warning signal and/or for stopping the knitting machine may take the form of one or more electric switches actuable by the carrier in moving from said first level to said second level. The or each switch may control operation of a visual and/or audible alarm device. Alternatively, or in addition, each switch may control stopping of the knitting machine.

The invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a purely schematic perspective view of part of a knitting machine in accordance with the invention,

FIGS. 2a and 2b are sectional side views of part of a practical embodiment of a knitting machine according to the invention,

FIGS. 3a and 3b are plan views corresponding to FIG. 2a and 2b,

FIG. 4 is a side view of part of the machine shown in FIGS. 2 and 3, this view being taken in the direction of the arrow X in FIG. 3, and

FIG. 5 is a section taken on the line V-V of FIG. 4.

In FIG. 1 the reference numerals 1 and 2 designate two needle beds of a V-bed flat knitting machine, each bed having needles 3 slidably mounted in tricks 4 formed in the bed in conventional manner. The numeral 5 designates a cam box associated with the needle bed 1, this cam box being arranged to reciprocate along the needle bed to actuate the needles 3 of the bed 1 between a lower and raised position. A similar cam box (not shown) is associated with the needle bed 2 and the cam boxes of the two needle beds are connected to one another by bridge members 6, 7. A carrier 8 is secured at its ends to the bridge members 6 and 7 and lies above, and substantially parallel to, the gap 9 between the needle beds. Depending from the carrier 8 are two hold-down elements serving the purpose mentioned above.

The parts so far described are known in V-bed knitting machines, one practical embodiment of a machine of this kind being described in the aforesaid Specification.

Referring again to FIG. 1, it will be appreciated that each needle 3 must descend in its needle bed prior to the movement of a hold-down element 10 or 11 past the needle in question. If, for any reason, a needle 3 does not descend in its needle bed, then this raised needle will be struck by one of the hold-down elements with resulting damage to the raised needle and/or to the hold-down element and possibly to the needle beds and other needles. The effect of such a collision between a raised-needle and a hold-down element will be to bend the upper part of the needle downwardly and to force the hold-down element upwardly.

In the knitting machine shown in FIG. 1 the carrier 8 has its ends received in brackets l2, 13 secured to the bridge members 6, 7 respectively. In each of these brackets, the corresponding end of the carrier 8 is free to rise under the influence of an upwardly-directed force on the carrier 8, for example due to a hold-down element striking a raised needle.

Associated with each of the brackets 12, 13 is a respective micro-switch 14, having its contact-actuating member in a position where it is actuated by upward movement of the corresponding end of the carrier 8. Each of these micro-switches is connected into an electrical circuit controlling the actuation of a visual and/or audible alarm device. Alternatively, or in addition, each of the switches 14, 15 can control means for stopping the knitting machine.

When the knitting machine shown in FIG. 1 is operat ing normally, the carrier 8 is in its lowermost position in relation to the brackets 12, 13 and the switches 14, 15 are not actuated. This is the first level of the carrier referred to above. If now one of the needles 3 accidentally remains in a raised position, it will be struck by one of the hold-down elements 10, 11 as the cam boxes traverse the needle beds. As a result, at least one end of the carrier 8 is raised in its associated bracket 12, 13 and at least one of the switches 14, 15 will be actuated. This is the second level" of the carrier referred to above. The machine will then either stop automatically or the machine operator will be warned that the holddown element has encountered an obstruction. The obstruction can then be cleared and any damage can be repaired so that defective fabric is not produced in the machine.

FIGS. 2 to 5 show how the invention may be applied to the knitting machine described in the aforesaid Specification. In these Figures, the numeral 8 designates the carrier which supports the two hold-down elements (not shown), this carrier being supported at its ends in brackets generally designated by the numerals 12, 13 secured to bridges 6 and 7, respectively, 'extend ing between the cam boxes (not shown) of the machine. For the sake of comparison, the carrier 8 is the equivalent of the side plates 40 and 41 of FIG. 4 of the aforesaid Specification and the bridges 6 and 7 are the equivalent of the bridges 42 and 43 of FIG. 3 of the aforesaid Specification.

The bracket 12 has a base member consisting of a block 21 formed integrally with a flange 22. The flange 22 is secured to a distance piece 23 by means of bolts 24, the distance piece 23 being secured to the bridge by means of bolts 25. The block 21 has an elongate recess 26 formed therein, the axis of this recess being vertical and the cross-section of the recess being a segment of a circle. Pivotally mounted on the base member 20 is a bifurcated member 27, having the form of a channel section member with spaced-apart parallel flanges 29 joined by a web 30. A boss 31 of circular cross-section is secured to the web by means of bolts 32 with the axis of the boss 31 parallel to the flanges 29. The boss 31 is received in the recess 26 of the block 21, in which it is a sliding fit.

The boss 31 is formed with an outer sleeve 33 of circular cross-section and an inner sleeve 34, the latter having screw-threaded engagement in the outer sleeve 33. By rotating the inner sleeve 34 its position can be adjusted in the axial direction in the sleeve 33, so that the position of the lower surface of the boss 31 can be adjusted with respect to the member 27. The lower surface of the boss 31 rests on a cylindrical support 35 secured in the lower end of the recess 26 in the block 21 by bolts 36. The bifurcated member 27 is retained in the base member 20 by a bolt 37 which passes through the inner sleeve 34 of the boss 31 and is screwed into the cylindrical support 35.

From the description so far, it will be appreciated that the bifurcated member 27 is mounted in the base member 20 for pivoting movement about the axis of the recess 26, and that the height of the bifurcated member 27 in relation to the base member 20 may be adjusted by rotation of the inner sleeve 34 of the boss 31. A pointer 38 is mounted on the outwardly-facing surface of one of the flanges 29 for cooperation with a graduated scale 39 secured to an outwardly-facing surface of the block 21 to facilitate vertical adjustment of the bifurcated member 27 to a desired position in relation to the base member 20.

In the outwardly-facing surface of each flange 29 of the bifurcated member 27 there is a vertically disposed groove 40 of dove-tail section. In each of these grooves a slide-block 41, 41, respectively, is slidably mounted, these slide-blocks serving to receive the opposite ends of a spindle 42 which passes through a vertically elongated hole 43 in each of the flanges 29, Each of the slide-blocks 41, 41 is urged downwardly in its associated groove 40 by gravity and a light spring 44 so that the spindle 42 is held against the lower edge of the holes 43. The springs 44 may be omitted, for example when knitting comparatively light yarn on fine gauge machinery.

The left-hand end of the carrier 8 is secured to the bifurcated member 27 by means of a ling 45 pivotally secured at one end to the carrier 8 by means of a horizontally disposed pivot pin 46 and pivotally secured at its other end in the flanges 29 of the bifurcated member 27 by a second horizontally disposed pivot pin 47. A foot 48 extending from the left-hand end of the link 45 engages under the lower end 49 of the web 30 of the bifurcated member 27 when the carrier 8 is removed leaving the link 45 on the pivot pin 47. The foot 48 then maintains the link 45 in an approximately horizontal position ready for re-connection of the carrier 8 when it is re-introduced. The surface 51 of the link 45 (the upper part of which is chamfered) bears against the adjacent lower surfaces of the side plates of the carrier 8 and determines the lowermost position which the lefthand end of the carrier 8 can adopt relative to the bifurcated member 27. At its left-hand end the carrier 8 has a horizontally disposed slot formed therein which receives the spindle 42.

The bracket 13 which supports the right-hand end of the carrier 8 is of similar construction to the bracket 12 described above, and the same reference numerals have been used to designate items in the bracket 13 which are similar to items of the bracket 12. There are, however, two main differences between the brackets 12 and 13. In the first place, the right-hand end of the carrier 8 is not linked to the bifurcated member 27 but merely rests on a horizontally disposed roller 55 rotatably mounted on a pin 56 secured at its ends in the two flanges 29. When the carrier 8 rests with its left-hand end on the surface 51 and its right-hand end on the roller 55, it is disposed at the first level referred to above. In the second place, the base member 20 of the bracket 13 is constructed in two parts, the block 21 being pivotally mounted on a horizontally disposed pivot 57 secured to the flange 22, the axis of the pivot 57 being susbstantially parallel to the axis of the carrier 8.

The base members of the two brackets 12 and 13 are connected by a rod 60, the ends of the latter being secured to the respective base members 20 by screws 61.

Two micro-switches 62, 63 are secured to the rod 60, one adjacent to each end of the rod. The actuating member 64 of each switch is disposed vertically above a proj; ction 41" on the slide block 41, the projection carrying the spindle 42 of the associated bracket 12 or 13. The actuating member 64 extends downwardly from the switch 63 through a tongue 28 bent outwardly from a sheet metal housing 63' for the switch 63. The tongue 28 acts as a stop limiting the upward movement of the projection 40" and thus of the carrier 8. The arrangement in respect of the switch 62 is similar.

In normal use of the knitting machine to which FIGS. 2 to 4 relate, the carrier 8 is reciprocated along the needle beds of the machine in the directions indicated by the arrow A by the bridges 6 and 7, so that the holddown elements are reciprocated along the gap between the needle beds. The height of the hold-down elements in relation to the needles can be adjusted by suitable adjustment of the inner sleeves 34 of the bifurcated members 27. If either of the hold-down elements has to ride over knitting which is over-tight, the hold-down element and carrier can rise slightly without operating the switch 62 or 63. If, however, either hold-down element strikes an obstruction, for example a needle which has failed to descend, at least one end of the carrier 8 is lifted far enough so that at least one of the spindles 42 is raised to cause actuation of one of the switches 62, 63 by a projection 41", the carrier then being at the second level referred to above. Actuation of the switch or switches can be used in any suitable way to initiate a visual and/or audible alarm, and/or to stop the knitting machine.

Instead of mounting the rod 60 on the flanges 22 (as shown in FIG. 4) which are fixed with respect to the brackets 12 and 13, respectively, the rod may be mounted on the bifurcated members 27. The rod 60 will then move up or down when the bifurcated members are adjusted vertically. In the form of mounting shown in the drawings, the position of the switches 62 and 63 remains unchanged on vertical adjustment of the bifurcated members. In other words, the level of the hold-down elements in relation to the needles at which the switches 62 and 63 will operate is fixed. In the case of the alternative mounting the distance by'which the hold-down elements must rise to operate the switches is fixed and it may be necessary to adjust the heights of the switch operating members after adjusting the members 27 vertically.

What is claimed is:

1. In a knitting machine having two cooperating arrays of latch needles arranged in opposed needle beds, means for independent actuation of successive needles in the arrays to move said needles between a lower and raised position, a carrier, support means positioning said carrier above said needle beds and movable longitudinally of the needle beds, and a hold-down element for holding down knitted loops as the needles rise, said hold-down element being supported from said carrier, the improvement comprising in combination mounting means for said carrier, said mounting means being fixed to said support means and said carrier being yieldably connected to said mounting means for movement between a first level below the level of the needles in their raised position, and a second level, said second level being higher than said first level, and switch means operable by movement of said carrier from said first level to said second level.

2. The knitting machine claimed in claim 1 wherein said support means comprises two supports located above said needle beds, said machine further comprising two brackets, one mounted on each of said supports, and said carrier being an elongate member supported at each end in one of said brackets.

3. A knitting machine as claimed in claim 2 also including two cam boxes co-operating with needles of the opposed needle beds wherein at least one of said supports is constituted by a bridge member secured to said two cam boxes and extending across and above the needle beds.

4. A knitting machine as claimed in claim 3 wherein each of said brackets is mounted on its associated bridge member so as to be capable of pivotal movement about an axis extending down between the needle beds.

5. A knitting machine as claimed in claim 4 wherein one of said brackets is mounted on its associated bridge member so as also to be capable of pivotal movement about an axis extending in the longitudinal direction of the needle beds.

6. A knitting machine as claimed in claim 5 wherein the carrier is urged to said first level by spring means.

7. A knitting machine as claimed in claim 6 wherein said means for producing a warning signal and/or for stopping the knitting machine comprise at least one electric switch actuable by the carrier in moving to said second level. 

1. In a knitting machine having two cooperating arrays of latch needles arranged in opposed needle beds, means for independent actuation of successive needles in the arrays to move said needles between a lower and raised position, a carrier, support means positioning said carrier above said needle beds and movable longitudinally of the needle beds, and a hold-down element for holding down knitted loops as the needles rise, said hold-down element being supported from said carrier, the improvement comprising in combination mounting means for said carrier, said mounting means being fixed to said support means and said carrier being yieldably connected to said mounting means for movement between a first level below the level of the needles in their raised position, and a second level, said second level being higher than said first level, and switch means operable by movement of said carrier from said first level to said second level.
 2. The knitting machine claimed in claim 1 wherein said support means comprises two supports located above said needle beds, said machine further comprising two brackets, one mounted on each of said supports, and said carrier being an elongate member supported at each end in one of said brackets.
 3. A knitting machine as claimed in claim 2 also including two cam boxes co-operating with needles of the opposed needle beds wherein at least one of said supports is constituted by a bridge member secured to said two cam boxes and extending across and above the needle beds.
 4. A knitting machine as claimed in claim 3 wherein each of said brackets is mounted on its associated bridge member so as to be capable of pivotal movement about an axis extending down between the needle beds.
 5. A knitting machine as claimed in claim 4 wherein one of said brackets is mounted on its associated bridge member so as also to be capable of pivotal movement about an axis extending in the longitudinal direction of the needle beds.
 6. A knitting machine as claimed in claim 5 wherein the carrier is urged to said first level by spring means.
 7. A knitting machine as claimed in claim 6 wherein said means for producing a warning signal aNd/or for stopping the knitting machine comprise at least one electric switch actuable by the carrier in moving to said second level. 